Infection Myths That Keep Circulating — and What the Evidence Actually Shows

The association between winter and colds is real, but the cause is indirect. People spend more time indoors in close proximity during colder months, which increases the opportunity for respiratory viruses to spread from person to person. Some research also suggests that cold, dry air may slightly impair certain nasal defense mechanisms, but exposure to a virus remains the necessary condition for infection. Stepping outside without a coat will not give you a cold.

This saying has circulated for centuries, but modern nutrition and immunology research does not validate it as a therapeutic strategy. Fever raises the body's metabolic demands, meaning the body may actually need more energy, not less. While appetite naturally decreases during illness — a well-documented physiological response — intentionally withholding food is not recommended. Staying well hydrated is consistently supported; eating according to appetite and tolerance is the practical guidance most clinicians offer. For a fuller examination of fever beliefs, see fever myths that many adults still believe.

Influenza, for example, can be contagious from roughly one day before symptoms begin. Several other respiratory viruses share a similar pre-symptomatic infectious period. This is one reason public health guidance emphasizes handwashing and respiratory etiquette as ongoing habits rather than responses reserved for when you feel sick. It also underlines why staying home once symptoms do appear matters — by that point, you may already have been infectious for hours or days.

Taking antibiotics for a viral illness exposes you to potential side effects — including gastrointestinal disruption and allergic reactions — with zero therapeutic benefit. More significantly, unnecessary antibiotic use is a primary driver of antimicrobial resistance, a serious public health problem. If a bacterial complication develops during or after a viral illness (such as bacterial pneumonia following flu), a clinician may then prescribe antibiotics. That decision belongs to a healthcare provider based on clinical evaluation, not on the patient's preference for a faster recovery. Our article on antibiotic course misconceptions explores related myths in more depth.

The reasoning behind completing a full antibiotic course has been debated and refined in medical literature, and guidance varies by specific infection and drug. However, the core message from prescribers remains: do not alter the course on your own. Some bacteria may persist in reduced numbers after symptoms resolve, and an incomplete course can select for those with greater resistance. Any concerns about duration or side effects should be discussed directly with the prescribing clinician, not addressed by self-discontinuation.

Decades of research, including large reviews of clinical trials, have found that routine vitamin C supplementation does not significantly reduce cold incidence in the general public. Some evidence suggests modest reductions in duration, but the effect size is small. For individuals with severe vitamin C deficiency, supplementation can restore normal immune function — but this is different from megadosing as a therapeutic strategy. A balanced diet remains the most evidence-supported way to maintain micronutrient levels that support immunity. See also our article examining myths about vitamin supplements.